Rapeseed oil transesterification catalyzed by sodium phosphates

This paper examines the activity as a catalyst of sodium phosphate compounds to produce methyl esters of rapeseed oil. The research shows that the transesterification of rapeseed oil by methyl alcohol could be efficiently catalyzed by both anhydrous and hydrated trisodium phosphate, while polytrisodium phosphate has only a negligible catalytic activity. Trisodium phosphate catalysts are less active than sodium hydroxide due to the lower ability to form sodium methoxide. However, these catalysts can lead to decreasing the number of technological stages and the amount of unwanted waste products. The experimental data are interpreted by using a kinetic model showing that a first-order reaction with respect to glycerides concentration is adequate to describe the reaction. This paper also indicates that under the selected experimental conditions, the chemical reaction is the main factor affecting the rate-determining step.